In general, communication systems permit data or other signals to be transmitted from a first device to a second device via a communication channel which may be established wirelessly or over electrical or fiber optic cable. When transmitting information, the signal may be referred to as data. Thus, a voice or video signal that is transmitted may nevertheless be referred to as data. Data may be bundled into pieces called packets, frames, blocks, or cells, all of which may have similar meaning, but the term packet will be used hereinafter to refer to any bundle of data. A packet may be organized in a specific form to aid transmission, for example having specific fields and/or specific fixed length fields. Each field is separated into symbols, such as orthogonal frequency division multiplexing (OFDM) symbols. Demodulation of OFDM signals is promoted by precise time synchronization at the receiver to determine the starting position of each OFDM symbol.